Chemically treated laundry bag



FABRIC OF H IGH-TENACITY I W. WHITEHEAD CHEMICALLY TREATED LAUNDRY BAGFlled May 31, 1946 June 5, 1951 Patented June 5, 1951 CHEMICALLY TREATEDLAUNDRY BAG William Whitehead,.Forest Hills, N. Y., assignor to CelaneseCorporation of America, a corporation of Delaware Application May 31,1946, Serial N0. 673,626

2 Claims.

This invention relates to a process for the treatment of textilematerials and relates more particularly to the treatment of fabricmaterials Woven, knitted, netted or knotted of continuous filament,high-tenacity regenerated cellulose yarns, whereby the resistance ofsaid fabric materials to laundering is substantially improved.

In the commercial laundering of garments and other fabric materials,strong chemical washing agents are employed to produce the desiredcleansing effect. White fabrics are usually subjected to the most harshconditions since the attainment of a bright color in the launderedmaterial usually entails the use of bleaching agents in addition to thecustomary soaps, chemical softeners and the like which are employed. Thenet eifect of these various compounds on cellulosic materials, forexample, is to produce a rapid tendering, degradation or weakening ofthe cellulosic fibers. This undesirable weakening effect is alsoobserved in the case of fabrics woven of high-tenacity regeneratedcellulose yarns formed by stretching and then saponifying yarns andfilaments having a basis of cellulose acetate or other organic acidester of cellulose. Various attempts have been made to increase theresistance of said high-tenacity regenerated cellulose fabric materialsto the harmful eifects of the chemical agents which are employed inwashing operations but the results obtained have not been entirelysatisfactory.

It is, therefore, an important object of this invention to provideimproved regenerated cellulose fabrics which are highly resistant to thetendering and degrading effect of laundering operations.

Another object of this invention is to provide a novel process for thetreatment of fabrics woven of high-tenacity regenerated cellulose yarnsand. filaments, formed by stretching and then saponifying yarns andfilaments having a basis of cellulose acetate or other organic acidester of cellulose, whereby the strength and service life of said fabricmaterials is substantially increased.

Other objects of this invention will appear from the following detaileddescription.

In the accompanying drawing, the figure represents a type of laundry bagmade in accordance with my invention.

I have now found that the strength and re sistance to laundering agentsof fabrics Woven, knitted, netted or knotted of continuous, hightenacityregenerated cellulose filaments formed by stretching and thensaponifying filaments having a basis of cellulose acetate or otherorganic acid ester of cellulose may be substantially improved bysubjecting said fabrics to treatment with an aqueous solution of analkali metal hydroxide before said fabric materials are subjected tolaundering operations. In accordance with my novel process, I immersesaid fabrics in an aqueous solution containing from 4 to 12% by weightof sodium hydroxide, or other alkali metal hydroxide such as potassiumhydroxide, at a temperature of 15 to 25 C. for 2 to 60 minutes and thefabrics so-treated are then rinsed, scoured and dried. The fabricsobtained by my process exhibit a very marked improvement not only instrength but also in their resistance to the degrading effects of thechemical agents employed in the laundering operations so that saidimproved fabrics are capable of under going a substantially increasednumber of laundering cycles without excessive tendering, degradation orrupture than fabrics heretofore employed. Optimum results are achievedemploying an 8% by Weight aqueous solution of sodium hydroxide for thetreating bath and maintaining the fabrics in said solution for about 20minutes with said sodium hydroxide solution at a temperature of about 20C.

While I preferably treat said high-tenacity regenerated cellulosematerials after they have been woven, knitted, netted or knotted intothe form of fabrics, it will be understood, of course, that thehigh-tenacity regenerated cellulose materials may be subjected to saidalkaline treatment in the form of hanks of yarn, and the like, and thetreated yarns then woven, knitted,

' netted or knotted into the desired fabric.

The high-tenacity regenerated cellulose yarns from which said fabricsare formed by Weaving, knitting, netting or knotting operations areobtained by stretching and then saponifying yarns having a basis ofcellulose acetate or other organic acid ester of cellulose. The yarnsare stretched during a suitable stage in their manufacture, and theyarns may be increased in length, as a result of the stretchingoperation, to the extent of 200, 300, 500, or even 1000 or 2000% oftheir original length. The yarns acquire a relatively high tenacity onbeing stretched, the tenacity being retained and in many instancesenhanced by the saponification which effects a regeneration of thecellulose. The resulting regenerated cellulose yarns are of greatstrength.

The saponification of the stretched yarns, as such or in a fabric form,may be effected by means of any suitable basic agents. The saponifyingagent may be inorganic in nature such as, for example, sodium hydroxide,potassium hy- For example, when aqueous solutions of sodium hydroxideare employed as the. saponifying, agent,

the sodium hydroxide may be presentin a concentration of from 0.1 to. 5%by weight and saponification may be effected in from I to 60 minuteswith the solution at a temperature of from 30 to 90 C. When employingaqueous solutions of sodium hydroxide as the saponifying medium, it ispreferable to include a salt such as sodium sulfate or sodium acetate insaid solution- To efiect the desired saponification, the stretched yarnsare led directly into the saponitying bath, therpath throughthesaponifyingba'th being sufficiently extended and the speed at whichthe yarns; pass through the bath being such that. theyarns, under theconditions of both temperature and concentration employed; arecompletely saponified before leaving the bath. Speeds of to l00'metersper minute are satisfactory.

The process of my invention is particularly valuable for the treatmentof those open-mesh fabric bags woven of high-tenacity regeneratedcellulose yarns which are employed in commercial laundering operations.During commercial laundering operations, the various types of garmentsto be laundered are sorted out and each groupof garments obtained isthen placed in. a loosely woven mesh bag which is closed and thenentered into the laundry wheel in which the washing operation takesplace. The mesh structure of the bag allows free circulation of thewashing solution and rinse water but retains the various garmentstherein so that they may be easily separated: from the many othergarments or bundles of garments which are usually washed at the sametime. While ordinary untreated open-mesh fabric bags woven of high--tenacity regenerated cellulose yarns lose a sum-- cient proportion oftheir strength to render them unusable after only a relatively fewlaundry cycles, the open-mesh high-tenacity regenerated cellulosematerials treated in accordance with my novel process retain theirstrength and are entirely satisfactory after a considerably greaternumber of cycles.

In order further to illustrate the novel process of, my invention, butwithout being limited thereto, the following example is given:

Example inch Z-twist plied together with the insertion of 11 turns perinch S-twist, the final yarn containing 2880 filaments. The regeneratedcellulose yarns employed are prepared by stretching a suitable celluloseacetate yarn nine times its original length, saponifying said yarn andthen twisting and doubling. The mesh laundry bag obtained is thenimmersed in an. 8% by weight aqueous solution of sodium hydroxide at 20C. for 20 minutes, after which the laundry bag is rinsed, scoured anddried. When loaded with clothesand. employed in the usual laundry cycle,the laundry bag so formed satisfactorily withstands a total of 150laundry cycles or more. Laundry bags: which have not been subjected tosaid alkaline treatment prior to being employed in the usual laundrycycle fail after undergoing the action of about'50 laundry cycles.Ordinary cotton laundry bags, of similar weight and construction forexample, fail after only 30 cycles.

It is to be understood that the foregoing detailed description. is givenmerely byway ofillustration and: that many variations may bemadethere-in; without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patentis:

1. As a. new article of manufacture, a fabric laundry bag having a basisof. high-tenacity regenerated cellulose yarns tormedby stretching andthen saponifying yarns having a basis of treated with an aqueoussolution of. sodium hydroxide.

WILLIAM WHITEHEAD.

REFERENCES CITED.

The following references are of record in the.

file of this patent:

UNITED STATES PATENTS I Date.

Number Name 2,020,303. Dreyfus, Mar. 12, 1935- 2,053,767 Dreyfus Sept.8, 1936 2,132,734. Hartet al Oct.11, 1938 2,173,241 Young Sept. 19,1939- 2,243,877 Mann .June 3., 1941. 2,252,554. Carothers Aug. 12, 19.412,289,085 Arnhem July 7, 1942 2,337,398- Marsh et al Dec. 21, 19.43v2,343,039 Smith Feb. 29, 1944. 2,352,707 Goldthwait July 4, 19442,416,747 I Geimer Mar. 4, 19.417 2,467,792 Wenzel et a1 Apr- 19, 19492,504,124 Hicls Apr..18f, 1950 2,511,664- Liss June 13, 1950.

FOREIGN PATENTS Number Country Date 501,768 Great Britain Mar. 6, 1939560,378 Great Britain Apr". 3, 1944

1. AS A NEW ARTICLE OF MANUFACTURE, A FABRIC LAUNDRY BAG HAVING A BASISOF HIGH-TENACITY REGENERATED CELLULOSE YARNS FORMED BY STRETCHING ANDTHEN SAPONIFYING YARNS HAVING A BASIS OF AN ORGANIC ACID ESTER OFCELLULOSE, WHICH LAUNDRY BAG HAS BEEN TREATED WITH AN AQUEOUS SOLUTIONOF AN ALKALI METAL HYDROXIDE.